Process of manufacturing acetyl mono-methyl aryl amines



T. CLARKE AND WIEBLIAELZ 'W. H ASSIGNOBS TO EASTMAN 7250171 11;

A, CORPORATION 0Z6 HE? 'iZQI-Ei ItOCE-SS OF TxlXANUFACT'URII TG? ABET" n, or

NEW" "51 Oiled--1,

Al i 1N l,4ll, li83. Specification Oi Letters *a'ten'l i l is, No Drawing. Application. filed January 2'3, 1521. aerial "No. 435,913.

ing acyl derivatives of niouoniethyl aryl amines. of which methyl acetanilid the most important commercially at the present time. One object of our invention is to proyicle a process which will be relatively inexpensive to carry out and yet will high yields of the desired substances. (l the: objects will hereinafter appear.

It has been previously stated by titaedel,

Berichte der Deutschen Chemisrlw-n Gesellschaft, volume 19, page lll le', tiat aretyl chloride at the usual temperature is without action on tertiary amines, whereas bemoyl chloride acts on dimethyl aniline. the latter statement being supported by a citation of Hesss work, same periodical, volume 15h page 685. ,Staedel also shows that an vl bromide reacts'with diniethyl aniline, so that monomethyl aniline can be produrrd, but explicitly says that this reaction constitutes a noteworthy difference between the bromide and chloride.

\Ve have found, however, that methyl acetanilid (otherwise known as aeetyl monomethyl anilin) and the analogous aryl amino substances, in which tolyl and naphthyl groups are present, may be prepared in yields closely approximating those that are theoretically possible if acetyl chloride be added to a boiling dimethyl :iryl amine, such as dimethyl anilin, at a rate suilicicntly slow to prevent the temperature of the boiling mixture falling below a critical tempcrat-ure, which is 160 C, for example, when diinethyl. anilin is employed. The reaction may be represented as follows:

In general this critical temperature well above the temperature at wluch an equirno lecular mixture of the ingredients would boil um.

rein); coiulitions. Since the lde is relatively much more vola acc'tyl c tile than mono-inetlrr the tempo! never could pass me 1.. .u. 03 v,- in, w pm. 1

eritical (iBE Il owing his mired substances lire boiling governing laws l or example. the heated hath. may K posed f dimethyl anilin or a. lure oi dimetoyl 'anilin and methyl acetanh lid. llirher 0 these hat W'll hoil under reflux conditions at atmospheric pressure in the nei rhhorlumd of 190 C. To either of these baths acetyl chloride or a mixture {preferably e uiniolecular) of dimethyl anilin and aretyl. chloride may be added, a small amount at a. time, intermittently, or in a small continuous stream, at, such a rate that the tempm'aturc does not fall much below 194) C. il hen ,,a.' equin'iolecular mixture of acetyl. chloride and (liniet-hyl anilin is zulded to the bath, the latter may be composed almost entirely of methyl acetanilid. lint this is not the preferred form. it is preferable to add the acetyl chloride or the mixture of this substance" with dimethyl anilin under the surface of the bath, any of the roll known means for making such addition tr .ur useful for this purpose. The boiling under reflux conditions is adequate to mix or agitate the liquids.

While we prefer to work at atn'iospheric pressure for convenience, nevertheless the r-ossurc may be varied somewhat without preventing the desired reaction from talz inn" place, the temperature being slightly altered by the change in pressure, as will he understood by those skilled in the art. Even when Working at atmospheric pressure the temperature may tend to rise somewhat owing to the formation of increasing amounts of the higher boiling methyl acetanilid in neighhorl'iood of 190 C.

the bath. This increase does noharm. The methyl chlhride formed during the reaction escapes through the condenser of the ordinary reflux apparatus, which may be em ployed, and may lie recovered.

"When sufficient methyl acetanilid has formed in the hath the mixture is cooled and the methyl acetnnilid, or acetyl monomethyl enilin crystallizes out and may be freed from unchanged dimethyl nnilin by filtration and washing with dilute acid or other known or preferred means.

By withdrawing part of the bath which rich in methyl acetanilid a nd simultene onsly adding an equivalent "amount of di methyl anilin to the bath the latter may be kept continually in use. The dimethyl anilin thus added to the bath in. the continuous form of our process may in part be composed of the dimethyl anilin, which is separate from the finished methyl acetanilid after proper purification.

Dilnethyl toluidines or the corresponding napht-hyl compounds may be used in place of the dimethyl anilin, as is obvious.

Having thus described our invention, what we claim new and desire to secure by Letters Patent is: i

1. The process of making acetyl monomethyl uryl amines which comprises reactin on a. dimethyl eryl amine with acetyl ch oride at a, temperature above the tempera-- ture at which. en equimolecular mixture of said ingredients would bull.

2. The process of mukingncetyl monomethyl anilin which comprises rue-acting on dimethyl anilin with acetyl chloride at a temperature above 160 C.

The process of making acetyl monomethyl anilin which comprises reacting on dimethyl anilin with .acetyl chloride in the 4. The process of making acetyl monomethyl anilin which comprises adding acetyl chloride to a heated hath containing dimethyl anilin at such a rate that the temperature of the bath does not fall below 160 (1.

5. The method of making ecetyl monomethyl acetanilid which comprises adding acetyl chloride to a boiling both containing dimethyl anilin while maintaining the temperature of the bath in the neighboorhood 6. The process of making an acetyl monomethyl aryl amine which comprises at'ldillg ecetyl chloride to a heated bath containing a dimethyl aryl amine at such a rate that the temperature of the bath does not fall below a reaction temperature above the temperature at which an. equimolecular mixture of such ingredients would boil, the aryl roup in said dimet-hyl aryl amine being the same as the aryl group in said derived acetyl mono-methyl aryl amine.

7. The process of making acetyl monomethyl unilin which comprises adding acetyl chloride to a boiling bath, under reflux con ditions. containing dimethyl anilin while maintaining the temperature of said bath at approximately 190 8. The process of making acetyl monomethyl anilin which comprises adding acetyl chloride below the surface of. a boiling bath containing dimethyl anilin while mainteim ing the tempenatureof said bath at approxi metely 190 C.

9. The process of producing acetyl monomethyl anilin, which comprises adding acetyl chloride below the surface of a boiling bath, under reflux conditions, containing di-methyl anilin while maintaining the temperature of the bath in the neighborhood of 190 (1., and finally cooling the resaltin mixture to crystallize the acetyl rnonc-meti iy] anilin thus produced. 7

10. The "rocess of making acetyl monomethyl anihn, which comprises adding acct l chloride to a heated bath containlng imethyl anilin and acetylmono-methyl anilin while maintaining the temperature of the birth above 160 11. The process of making acet-yl monotaining dimethyl ,zmilin and acetyl monomethyl anilin. I

Pigned et Rochester, New York, this 3rd day ct (Tannery, 1921f "rims T. CLARKE.

WILLIAM w. HARTMAN.

methyl anilin, which comprises adding a. 

